Manufacturing of metallic products generates a lot of waste and by-products; for instance, large quantities of steel dusts and other wastes associated with modern methods of steel production. Most steelmakers are searching for ways to recycle steel dusts, not only to lower the amount of environmentally hazardous materials, but also to allow steelmakers to reclaim valuable minerals otherwise lost as waste.
Steelmakers have developed methods of recycling steel mill waste by collecting the waste, combining the waste with a binder and compacting the combination into a solid agglomerate. The agglomerate may later be charged to a steelmaking furnace. Various types of binders have been suggested including: a water insoluble elastomeric polymer (U.S. Pat. No. 5,147,452), oleic acid, spindle oil, turbine oil and zinc stearate (U.S. Pat. No. 6,533,856), liquid sodium silicate, hydrated lime, powdered pitch and water (U.S. Pat. No. 4,116,679) and cellulose fiber (U.S. Pat. No. 6,802,886). Additional known binding materials for agglomerating fine metal particles include molasses and lime, and dry sulfite and water.
However, existing methods are not optimal, are expensive and/or inefficient for different reasons. For instance some existing methods may require a sintering step or an additional treating step which causes oxidation of the fines which thereupon requires an additional reduction step. Some methods may require expensive binders and/or require mixing the binder under heating. Some other methods are limited with respect to the type and/or purity of the iron-based powders that can be used. In addition, the solid agglomerate product obtained using these known methods may not have an acceptable resistance to crumbling, dusting or high temperature.
The present invention addresses these needs as it relates to a solid agglomerate of metal particles and methods of manufacturing same. In embodiments, the solid agglomerates possess a desirable density, a suitable resistance to crumbling and dusting during handling, which can resist to high temperature and resist to humidity.
Additional features of the invention will be apparent from review of the disclosure, figures, and description of the invention below.